Team Identifies Genetic Markers for Depression

DNA sequencing shifts focus from neurons to metabolism.

The search for a genetic link to
depression, which affects 350
million people worldwide, has
come up empty for years. While some
people become depressed after a mild
stressful event, others remain resilient to
catastrophe. A British researcher and his
team found two areas in the genome
that appear to be key to depression.

To make sure he recruited only
patients with major depression, Jonathan
Flint, a psychiatrist from the University
of Oxford who led the study, says he
examined older generations of Han
Chinese women. As a result, his patients
did not have many of the complicating
factors of depression. “None of them
drink alcohol, none of them smoke, and
other drug abuse is rare,” he says.

Flint’s team collected DNA samples
from more than 5,000 women with
major depression and an equal
number of controls. Gene sequencing
revealed two regions associated with
major depressive disorder on one
of the 23 pairs of chromosomes.
One was key because it lies near the
gene SIRT1, which is important for
the energy-producing parts of cells
called mitochondria.

The finding, reported in July, shifts the
focus of depression’s source from neuron
function to metabolism, which could
lead to more effective diagnosis and
drug treatments, Flint says.